Process fob making gasoline



O. BEHIMER PROCESS FOR MAKING GASOLINE Feb. 14, 1928; Re. 16,877

Original Filed Nov. 2lI 1918 Juventa@ Reissued Feb. 14, 1928.

UNITED STATES OTTO BEHIMER, OFy PORT ARTHUR, NEW YORK, N. Y.,

TEXAS, ASSIGNOR T THE TEXAS COMPANY, OF A CORPORATION DELAWARE.

PROCESS FOR MAKING GASOLINE.

Original application led November 21, 1918,

Serial No. 263,562. Divided and application filed April 6,

1923, Serial No. 630,242. Divided and application filed August 13, 1925,Serial No. 49,962. Original v No. 1,585,496, dated May 18, 1926.Application in Canada Decemberu, 1921.

This invention relates to methods of making condensable light oils, suchas gasoline. More particularly it relates to certain novel improvementsin the cracking of hydrocarbons whereby higher boiling hydrocarbons aredecomposed into those of lower boiling point.

This application is a division of my copending application, Serial No.630,242, tiled 0 April 6, 1923, which itself is a division of mycopending application, Serial No.

263,562, tiled November 2l, 1918.

ln rior methods of cracking hydrocarbon oils, considerable difficultyhas been ex- 5 perienced on account of carbon formations, which occur onthe sides of tubes and stills exposed to the heat required to carry onthe cracking operation. f.

It is a broad novel feature of the herein disclosed process thatsubstantially all of the cracking operationroccurs in a vessel to whichno external heat is applied, except at such times and in such quantitiesas are necessary to compensate for heat losses, the oil prior to itsintroduction to such vessel having been subjected to a high degree ofcracking heat and the excess heat of the oil itself being used to effectits own decomposition. As a consequence, I avoid substantial carbonformation of the Idestructive character which has proved such animpediment to prior systems. The removal of the cracking operation fromthe heating zone also reduces the danger from fires such as frequentlyoccur where cracking is carried on in highly heated stills and coilsexposed to direct heat.

More specially my process preferably einbodies a novel cyclic system inwhich a circuit of oil is constantly maintained under `varying liquidand vapor phases. The oil to be treated on entering this circuit issubjected to a high degree of heat, but the time element is socontrolled with respect thereto that there is comparatively littledecomposition and deposition vof carbon While it is exposed to thisexternal heat, the oil being rapidly removeglfrom the heating zone andconducted to the cracking zone, where without necessarily beingsubjected to additional heat, it undergoes a moleculardecomposition forreissue filed .Tune 24, 1927, Serial No. 201,273, and

whereby carbon and light products are formed and liberated. It Will beunderstood that oil cracking or conversion is dependent not only upon'the relative condi* tions of pressure and temperature but also upon thetime element With respect thereto, that is, the necessary' pressure andtemperature must be maintained for a sutiicient period of time to enablethe molecular decomposition or conversion to take place. According tothe present invention, this time factor is so controlled, by regulatingthe rate of heating the. -oil passing throughthe heating zone that thetemperature thereof is progressively raised in transit and reaches thedesired cracking temperature near the end of the heating coil at aboutthe time or a little before the oil emerges therefrom. Thus, althoughthe oil is subjected to cracking heats in the heating zone, thistemperat-ure is'attained only just previous to the eXit of the oiltherefrom, and therefore, the oil leaves the heating coil before anysubstantial decomposition and incident deposition of carbon takes place.

decomposition, is delivered to the cracking Zone, where the des1redvtemperature and pressure conditions, are continuously susincidentdecomposition of carbon are effected. The bulk of the carbon is removedfrom the circuit by withdrawing from the cracking zone, portions of theresidual oil. Although the process, in its broad conception, is completeat this stage of the operation, the light products preferably continueSubsequently, the highly heated oil'in a state of incipientv under apressure sufficient to insure the desired l lmolecular transformation.-

j so tained and the cracking of the oil and the those of the prior art,in which a circuit of liquid residuum is kept in circulation. lVhen suchoil is kept in circulation, considerable quantities of carbon areformed, owing to the readiness with which this type of oil earbonizeswhen exposed to high temperatures, the carbon forming in line particlesin the oil, and wherever it comes in contact with the heated metalsurfaces, it attaches itself thereto and builds up deposits, which oftencause the clicking of tubes and coils. It also crystalizes the metalsurfaces, thereby decreasing the tensile strength of the metal andcausing the bulging and breaking of such surfaces. Any residual oilresulting from the cracking operation will necessarily contain aconsiderable amount-of heavy polymerization products and carbon held insuspension in the oil, and to `circulate such a residue through heatedtubes is to continually pass into or produce in such tubes a largeamount of free carbon. rIn mysystem, I do not circulate a residuum, butinstead keep the residual oil removed from the application of externalheat and withdraw the heavier portions thereof, which contain the bulkof the carbon, from the cycle at the cracking zone, and continue thecycle by means of the vapor generated, which contains the condensableproduct desired and also certain heavier vaporous constituents which areused to complete the cycle. By removing the heavier residuum from thecycle, I keep the circuit free from this source of carbon formation, andsince I conduct substantially all of the cracking in a vessel to whicheither no external heat is applied or only a small quantity of heat isapplied to maintain the requi-V site temperature conditions, I am thusable to effectively remove the carbon formed.

In cracking oil for gasoline, there is gellerally formed a considerablequantity of vapors heavier than gasoline, which may be generallydesignated by the term, kerosene. I preferably employ these heaviervapors as a. carrier for the lighter vapors; they assist y `inmaintaining a current of vaporby which the gasoline is removed fromthecracking zone to a separator where the kerosene vapors'are condensedand removed from the gasoline vapors which pass on to the condenser. Thekerosene condensate, preferably at .a temperature, not materially belowits boilinfr point, is injected or otherwise suitably fbrced into theheavy oil charge entering and flowing through the heating tubes wherebya foamy agitated mixture 1s produced by the acceleration of thecirculationl in the heat-ing tubes resulting from the increased volume,pf oil therein, thereby preventing the settling, and flow of theheavier portions of the oil along the bottom of the highly heated tubesvand the consequent local overheating and carbonization of the. oil,

lhighl sists in maintaining the proper temperatures in the heating andcracking zones. By maintaining these bodies in constant circulation, thekerosene constituents, which under cxisting methods have been found sodifficult te decompose into lighter products, are, in my system,ultimately reduced to. gasoline.

I have devised certain novel apparatus which is adapted for carryingoutl my process, and illustrates the preferred form thereof in thedrawing in which,

y Figure l is a diagrammatic elevationY of said apparatus; Y

yFigure 2 is a` detail View of a modified cracking drum which may besubstituted for that of Figure l. i

It will be understood that other apparatus besides that illustrated maybe used in carrying out my process.A

Referring to Figure 1 of the illustrative drawings, a tubular heatingcoil 1 is located in a furnace '2, having a burner 3 and a stack 4. Asshowny for illustrative purposes, the coil 1 comprises a plurality ofhorizontally disposed rows of tubes extending through the furnace. andplaced the one above the .by vertically disposed return bends ortittlngs, as shown 1n F lgure 1, to forma singlel elongated andcontinuous heating coil through which the oil flows and is heated to therequired degree. This coil is of extended length and restrictedcross-section' and has a relatively large and effective heating surfacewhereb the' stream of oil passing therethrough 1s enabled to efficiently'absorb heat and reach a high temperature with rapidity. A checkeredbrick baille 5 having openings G may serve to distribute the heatevenly-over the coil. `A fresh oil charging line 7, having a jet orinjector 7, extends to a pump 8, which is connected to a'suitableLsource of oil supply (not shown). The pipe 9, having a valve 10, extendsfrom the heating coil 1 to an'enlarged, cracking drum or chamber11,"within which it may terminate in a. distributor 9". This distributor9aL may be of any suitable form to thoroughly distribute and dffuse thecharging oil throughout the of oil in the drum whereb anV intimatecontact of the heate of oi in the drum is effected. The cracking drumris preferably provided with a charging oil with the body jacket 11a ofsuitable insulating material to protect it against heat radiation andis.

4 .placed in the vapor line 16 but 1 preferto ymaintain the pressure inthe heating coil,

cracking drum and separator through the condenser. The y outlet 19terminates in a collecting tank 21, having a valved gas outlet 22 and avalved distillate outlet 23. The condensate line 17, which is preferablyin sulated, as indicated at 17h is equipped with i a valve 17 and isconnected to the charging lhne 7 at the ]et 7a.

In conducting the process with the apparatus illustrated, the oil to betreated is forced through the charging line 7 under considerablepressure, and is rapidly flowed through the heating coil 1, Where it isheated to the desired cracking temperature. Preferably this temperatureis somewhat higher than the temperature at which it is desired toconduct the cracking operation and may or may not result in substantialvaporization. The oil on beingr forced through the coil acquires a highcracking temperature, but on account of the rapidity of its flow,decomposition is only in the incipient stages when the oil is dischargedthrough the pipeV 9 into the heat insulated cracking drum 11 where aconstant body of oil is maintained at a cracking temperature underpressure. The distributor 9*, Aif employed serves to discharge the oilinto the cracking drum in a wide stream, thus thoroughly mixing the hot'oil with the liquid body of oil maintained inthe drum and diffusing theheat therethrough. This heat diffusion is matcrially aided by using adistributor with serrated edges. The rapid flow of the oil through thecoil where it is closely conlined is here suddenly retarded, as the oilenters the drum which is of ample volume. Thus, the excess heat of theoil operates to maintain the body of oil at the desired crackingtemperature and molecular decomposition and distillation are carried. onvigorously, the higher boiling hydrocarbons continually breaking up into`hydrocarbons of lower boiling point.. The vapors and gas gen-v eratedgather in the lupper part of-the cracking drum and pass out through thevapor outlet 13'to the separator 15,l where there is ,effected aseparation of hydrocarbons of desired volatility from those of lessvolatility. The hydrocarbons of the desired volatility pass out throughthe vapor line 16, by which they are conducted to the condenser 18,Where they are condensed,r and the condensed distillate is eitherintermittently or preferably continuously allowed to I run into thecollecting tank 21.

The temperature in the air condenser 15 is such that the less Volatilehydrocarbons are condensed and dropped into the conduit 17, by whichthey are conducted while still hot to the jet in the charging line orother suitable device for forcing the condensate into the chargingstream. The separator is preferably somewhat elevated so as to give aconsiderable head of liquid in the pipe 17, which preferably contains aU bend, as illustrated, in order to form a liquid seal therein. Thishead of liquid, together With the high'pressure at which the oil in thecharging line passes the j-ct, this pressure being ordinarily from 50 to100 pounds higher than the pressurc'in the drum, insures that thecondensate shall be constantly and positively drawn into ,the chargingline and forced into the coil 1. The introduction of this hot condensateinto the charging line increases the volume of oil in the heating coiland thereby accelerating the flow therein and producing a foamy mixtureso that -local overheating is prevented and the coil is keptsubstantially free from any slight carbon formations. 'lhis condensateconsists in a type of hydrocarbon which When decomposed does not yieldany great amount of carbon so that the oil charge is constantly beingdiluted with oil capable of being decomposed into lighter productswithout the production of i large amounts of carbon. This condensatereaches the jet in a heatedcondition, preferably at a temperaturenotmaterially below its boiling point, so as to heat` the charge of oilentering the heating coil.. The heat cycle formed by the keroseneconstituents contributes to the maintenance of the proper temperaturesin the heating coil and the cracking drum. By injecting or other- Wisesuitably forcing this condensate into the heating coil, I increase thevolume of oil {iowing therein without increasing the total amount of oilcharged into the system at any given time.

A considerable pressure is maintained throughout the system, Whichpressure is regulated byy means of the valve 20 or the valve on thegasoutlet 22. The pressure user l varies with the character of the oiloperated on and the character of the product desired. lOrdinarilyy thedecomposition in the cracking drum is carried on under a pressure offrom to 400 pounds. In utilizing oils of the type coim'nonly eniployedfor decomposition into products of -the nature of gasoline a temperaturein (he drum 11 of from 700 F'. to 850o with a tein- `perature in thecoil 1 of from 700O F. to 950"a lull lll)

is maintained a constant body of oil in the lss cracking zone.

It is desirable to equip the apparatus with the valvesv 10 and 17* sothat in case there is a break in the heating coil the eect of any tireresulting may be localized by4 closing said valves, whereby the bulk ofoil in the system will be retained in the cracking drum 11. It isunderstood that in the normal operation of the process, these valves areopen.

Auxiliary heat may be supplied to the cracking drum in any suitablemanner if desired, and a convenient method of providing this auxiliaryheat is, as shown in Figure 2, to insulate only the upper part of thedrum and apply heat at a moderate temperature or in a relatively smallquantity from any suitable heater such as is designated 30. In the earlystages of a run, since there is Vno danger of overheating a carbon-freesurface, the drumunay be heated freely until the necessary heat cyclehas been generated and decomposition has begun. For this reason thearrangement of Figure 2 possesses certain advantages over that ofFigure 1. But when `decomposition begins, with a consequent depositionof carbon, the heat must be reduced, as otherwisetlie carbon wouldaccumulate on the-hot surfaces and build up tenacious formationsthereon, thus preventing the e'ectual removal of the carbon andasphaltic bodies. As the run eontinues,only a moderate heat is applied,suiicient only to oiset the loss of heat due to radiation anddistillation. If desired the drum may be v heated by means of Waste heatfrom the furnace 2 0r in any other suitable manner.

The product obtained by the herein disclosed process is, for a crackedproduct, remarkably sweet, in other words, low in unsaturated compounds.

It is understood that I use the terms gasoline and kerosene iii thisapplication by way ofexample and that these terms are' taken as' typesof other similar distillates which may be producedby my process. I usethe term gasoline as an example oi': the volatile depends upon thetemperaturetherein under the pressures used.

Although for illustrative purposes the invention has been shown anddescribed in connection with apparatus of more or less specific detailsof construction, arrangement and location of parts, and as embodying inits mode of operation a certain series and sequence of. somewhatdefinite steps and operating conditions, it will be understood that manyof the objects and advantages of the invention may be obtained, to agreater or less extent, through the employment of apparatus of modifiedcharacter, or, in fact, through variations or, in some cases, omissions,of certain Vof the component steps, without departing from the spiritand scope of the invention.

lVliat I claim is: 'v

1. The process of converting hydrocarbon oil which comprises orcin saidoil through a coil and drum while app ying heat to said coil and drumand allowing the vapors generated to develop pressure untildecomposition of the hydrocarbon begins, then reducing the heat appliedto the drum while securing it against substantial loss of heat throughradiation and vaporization, and continuously supplying to the oil in thedrum the necessary heat for decomposition by means of the stream of oilenteringk from the coil, the stream entering the coil being continuouslycommingled with a hot condensate separated out from the generatedvapors.

2. The'process of converting hydrocarbon oil which comprises forcingsaid oil through a coil and drum while applying heat to said coil anddrum and allowing the vapors generated to develop pressure untildecompositionof the hydrocarbon begins, then reducing the heat appliedto the drum while securing it against substantial loss of heat throughradiation and vaporization, and continuously supplying to the oil in thedrum the necessary' heat for decomposition by means ofthe stream of oilentering from the coil.

3. The process of converting hydrocarbon v voil that comprises forcing astream of oil through an elongated stricted cross-section an largedchamber while lapplying heat freely to both said passageway and saidchamber to rapidly raise the oil to a cracking tein- `pera-ture anddevelop a superatmosphcric cracking pressure therein and, after saidconditions of temperature and pressure have been attained, applyin tosaid enlarged chamber reduced or mo erate heat suicient only to maintaina cracking temperat-iire iii said chamber while `continuing the freeapplication of heat to said passageway.

4. The process of converting hydrocarbon oil that comprises passing s.stream of oil passageway ot rec thence into an euioo Vis maintained,

through an elongated passageway of restricted cross-section, and thendelivering it into an enlar ed zone where a body of oil freely heatingthe oil in said passageway and in said enlarged zone durlng the startingperiod until cracking conditions of temperature and pressure areestablished, and subsequently continuing the free heating of the 011 insaid passageway but applying to the body of oil in said enlarged zone areduced and moderate amount of heat sufficient to oset heat losses andto maintain a cracking temperature therein throughout the period ofnormaloperation. 5. The process of converting hydrocarbon oil thatcomprises freely heating a moving said drum at a reduced and moderaterate I while continuing to freely heat the oil in l the coil, removinthevapors from the dis-l tillation drum, and separating out andreturning to the heating coil the condensed heavier fractions thereof.

In Witness whereof I have hereunto set my hand and seal this 8th day ofJ une-1927. OTTO BEHIMER.

